I’m still trying to find the exact source, but I wanted to clarify what I am talking about. I was talking about the idea of seeing anything that can fall under the category of pritzus/tumah. I think it is pretty clear that this is assur/problematic for men and women (aside from the fact that I was told by a Rav whom I asked that it is) whether it’s an actual halacha or a middah. Different people may categorize pritzus differently according to their levels of sensitivity, so exactly what falls under that category may be subjective, and some people’s sensitivities can sound extreme to others who may be on a different level of sensitivity.
Also, according to the Shulchan Aruch, you are not even supposed to be untznius in the privacy of your home (as in having anything uncovered that is normally covered, meaning even walking around w/o socks if you normally wear socks) so I would think it’s a kal v’chomer to seeing someone else dressed untzniusly (for no purpose). Rav Moshe Feinstein, zatsal says that it’s a midas chassidus. However, it still is something to strive for, each on his/her own level, and it is brought down in the Shulchan Aruch.
If this is hard to relate to, think about it in less extreme terms. I think that everyone would agree that there are things that girls shouldn’t see; some people will have different levels of sensitivity regarding what they think is a problem. I would give examples of what I mean, but if I do, the moderators won’t let this post through (rightly so).
I am not talking about the issurim that men have of not seeing women dressed untzniusly. I am talking about the general concept of staying away from tumah, and making sure that your thoughts are tahor and kadosh. That is something that applies to women as well as men and possibly, more so.